In-mold coating is a known technique for decorating or priming the surface of an article formed in a matched die mold under heat and pressure. A coating powder, which can be an unsaturated polyester formulation, is applied electrostatically to the interior wall of the mold. The powder melts and coalesces on the hot mold surface to produce a uniform coating. The fill resin, which constitutes the bulk of the finished article, is then inserted in the mold and heat and pressure is applied. When the cures of the coating and fill resin have advanced sufficiently and said resins are integral, the mold is opened and the molding is removed. It has been found desirable that the coating and fill resins be cross-linked across the interface between them to maximize the adhesion of one to the other.
The following patents relate to in-mold coating techniques of the type used in this invention: